1. Field of the Invention
The present invention relates to a cover of an openable motor vehicle roof with a cover plate, an edge gap seal, and a peripheral plastic frame which is foamed or injected onto the edge of the cover plate.
2. Description of Related Art
Covers for an openable motor vehicle roof are generally known, as shown for example, from the German patent DE 197 20 389 C1. When such a cover freezes up during the cold seasons, the cover adjustment function in the roof cutout is no longer ensured. In the case in which the cover is still movable, there is a danger that the seal which is provided around the cover plate or on the edge of the roof opening will be damaged during such movement because the seal is at least partially frozen tight. Another disadvantage of such a cover, which conventionally consists of glass or plastic, is its moderate heat insulation. Thus, cold emitted into the passenger compartment is perceived by the driver and passengers in the head area and is very unpleasant. Therefore, users often close the sliding head liner provided under the glass cover. This, however, greatly reduces the otherwise existing benefit of a glass roof in the form of additional light incidence from above.
The published German application DE 35 00 436 A1 discloses a glass cap roof which consists of a glass plate which is sealed by a sealing section along the peripheral edge of the vehicle roof cutout. The reference discloses that at least one heating wire is inserted into the sealing section between the glass cover and the roof cutout in the immediate vicinity of the edge gap in order to prevent the glass cap roof from becoming frozen solid. But here, the disadvantage is that the heating wire must be inserted into the sealing section in a relatively complex installation step. In addition, as the result of the elasticity of the sealing section and the heating wire""s very limited stretching capacity, the heating wire is exposed to loads which can lead to tearing of the heating wire.
The published German application DE-AS 12 16 128 is also noted for disclosing an electrical heating device for a vehicle door in which an electrical heating wire of a resistance heating wire heating system is inserted into a groove of the door frame that surrounds the door recess and can be connected to the vehicle battery via an actuation contact.
In view of the above discussed prior art, the primary object of the invention is to provide a cover for an openable vehicle roof which is also operable in the cold seasons.
Another object of the present invention is to provide such a cover which is easy to install and service.
Yet another object of the present invention is to provide such a cover which is reliable and minimizes the heating wire""s exposure to loads that can tear the heating wire.
These and other objects are achieved by providing an arrangement of a heating means in the plastic frame of the cover which is torsionally stiff to such an extent that the heating means located in it is not exposed to mechanical loading. Moreover, such arrangement of the heating means in the plastic frame allows comfortable and easy installation during manufacture of the cover, especially in the process of foaming-on the plastic frame, and optionally also during a subsequent installation step such as during service.
According to one advantageous embodiment of the present invention, there is a recess on the bottom and/or the outside of the plastic frame into which the heating element or heating means is clipped, the heating means being preferably in the form of a heating wire. Alternatively, the heating element can also be embedded directly into the material of the plastic frame at the same time as peripheral foaming is done, the heating element being embedded preferably near the bottom facing the interior. In one alternative embodiment, the heating element is attached to the reinforcing frame beforehand, i.e. before the material of the plastic frame is foamed onto the combination of the reinforcing frame and the cover plate. The heating element can be fixed to the reinforcing frame, for example, by means of cementing. However, in yet another embodiment, the heating element is housed in a plug-in receiver and the plug-in receiver is slipped onto the outside edge of the reinforcing frame.
By arranging the heating element on the bottom of the plastic frame and thus, in a position opposite to the head area of the driver and passenger, and preferably, when the heating element is made in the form of a heating coil, a xe2x80x9cflat radiatorxe2x80x9d is attained so that the head area which is sensitive to heat is also heated. This results in increased comfort of the driver and the passengers in the cold seasons so that the sliding head liner can remain in the opened position.
These and other objects, features and advantages of the present invention will become more apparent from the following detailed description of the preferred embodiments of the invention when viewed in conjunction with the accompanying drawings.